Synthesis of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and derivatives

1986 ◽  
Vol 64 (3) ◽  
pp. 449-456 ◽  
Author(s):  
Arthur E. Martell ◽  
Ramunas J. Motekaitis ◽  
Eric T. Clarke ◽  
J. J. Harrison
Keyword(s):  
Order Rate Constant ◽  
Synthetic Approach ◽  
Diacetic Acid ◽  
Substituted Phenols ◽  
Reaction Conditions ◽  
Complex Species ◽  
First Order ◽  
Synthetic Approaches ◽  
Hydrolysis Of ◽  
Selection Of

Two synthetic approaches for the synthesis of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and derivatives are reported. The first involves conversion of N,N′-di(2-hydroxybenzyl)ethylenediamine to the diamide HBEDDA via reaction with formaldehyde and HCN followed by hydrolysis. Analysis of the species distribution curves of the Cu(II) chelates of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and its diamide, HBEDDA, and of the nature of the coordination in each complex species formed, suggest the selection of the reaction conditions most favorable for the Cu(II)-catalyzed hydrolysis of HBEDDA to HBED. The rate of conversion was found to be low, and the reasons for these findings are described. Iron(III) catalysis of the conversion of HBEDDA to HBED was found to be rapid and complete with a pseudo-first-order rate constant of 3.1 × 10−3 s−1 at 25.0 °C. The results provide the final step of a new method for the synthesis of HBED. The second synthetic approach involves reaction of N,N′-ethylenediamine-diacetic acid (EDDA) with substituted phenols and formaldehyde. These approaches appear to be general for the synthesis of HBED and derivatives.

scholarly journals The properties of a carboxylesterase from the peach-potato aphid, Myzus persicae (Sulz.), and its role in conferring insecticide resistance

1977 ◽  
Vol 167 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Alan L. Devonshire
Keyword(s):  
Insecticide Resistance ◽  
Myzus Persicae ◽  
Order Rate Constant ◽  
Preliminary Evidence ◽  
Exchange Chromatography ◽  
Potato Aphid ◽  
First Order ◽  
Different Strains ◽  
Hydrolysis Of ◽  
Peach Potato Aphid

Carboxylesterases from different strains of Myzus persicae were examined to try to understand their contribution to insecticide resistance. Preliminary evidence that they are involved comes from the good correlation between the degree of resistance and the carboxylesterase and paraoxon-degrading activity in aphid homogenates. Furthermore the carboxylesterase associated with resistance could not be separated from the insecticide-degrading enzyme by electrophoresis or ion-exchange chromatography. Homogenates of resistant aphids hydrolysed paraoxon 60 times faster than did those of susceptible aphids, yet the purified enzymes from both sources had identical catalytic-centre activities towards this substrate and also towards naphth-1-yl acetate, the latter being hydrolysed by both 2×106 times faster than paraoxon. These observations provide evidence that the enzyme from both sources is identical, and that one enzyme hydrolyses both substrates. This was confirmed by relating the rate of paraoxon hydrolysis to the rate at which paraoxon-inhibited carboxylesterase re-activated. Both had the same first-order rate constant (0.01min−1), showing clearly that the hydrolysis of both substrates is brought about by the same enzyme. Its Km for naphth-1-yl acetate was 0.131mm, and for paraoxon 75pm. The latter very small value could not be measured directly, but was calculated from substrate-competition studies coupled with measurements of re-activation of the diethyl phosphorylated enzyme. Since the purified enzymes from resistant and susceptible aphids had the same catalytic-centre activity, the 60-fold difference between strains must be caused by different amounts of the same enzyme resulting from mutations of the regulator gene(s) rather than of the structural gene.

scholarly journals Kinetic Evidence for Near Irreversible Nonionic Micellar Entrapment ofN-(2′-Methoxyphenyl)phthalimide (1) under the Typical Alkaline Reaction Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
M. Niyaz Khan ◽  
Yoke-Leng Sim ◽  
Azhar Ariffin
Keyword(s):  
Kinetic Analysis ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Total Concentration ◽  
Reaction Conditions ◽  
First Order ◽  
Order Rate ◽  
Alkaline Reaction ◽  
Pseudo First Order ◽  
Hydrolysis Of

The values of pseudo-first-order rate constants (kobs) for alkaline hydrolysis of1, obtained at 1.0 mM NaOH and withinCmEnT(total concentration ofCmEn) range of 3.0–5.0 mM forC12E23and 10–20 mM forC18E20, fail to obey pseudophase micellar (PM) model. The values of the fraction of near irreversibleCmEnmicellar trapped1molecules (FIT1) vary in the range ~0–0.75 forC12E23and ~0–0.83 forC18E20under such conditions. The values ofFIT1become 1.0 at ≥10 mMC12E23and 50 mMC18E20. Kinetic analysis of the observed data at ≥10 mMC12E23shows near irreversible micellar entrapment of1molecules under such conditions.

Kinetics and mechanism of the reaction of dimethyl acetylphosphonate with water. Expulsion of a phosphonate ester from a carbonyl hydrate

1978 ◽  
Vol 56 (13) ◽  
pp. 1792-1795 ◽  
Author(s):  
Ronald Kluger ◽  
David C. Pire ◽  
Jik Chin
Keyword(s):  
Rate Constant ◽  
Electronic Effect ◽  
Order Rate Constant ◽  
Ion Concentration ◽  
First Order ◽  
Cleavage Reactions ◽  
Ph Range ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of ◽  
Mechanism Of The Reaction

Dimethyl acetylphosphonate (DAP) is rapidly cleaved in water to acetate and dimethylphosphonic acid. The half time for reaction at pH 7, 25 °C is estimated to be 3 s. The reaction is first order in hydroxide ion concentration and first order in DAP concentration. Rates of reaction were measured over the pH range 3.8 to 6.5 at 25 °C, 6.5 and 7.0 at 5 °C, 4.5 to 6.5 at 35 °C, and 4.5 to 6.0 at 45 °C. The average observed second-order rate constant at 25 °C is 2.4 × 106M−1 s−1. DAP is converted rapidly to a hydrated carbonyl adduct. The mechanism for the formation of the observed products is proposed to be analogous to cleavage reactions of other carbonyl hydrates, proceeding from a monoanion conjugate in this case. The estimated rate constant for the unimolecular cleavage of the carbonyl hydrate anion is 2 × 103 s−1. The rapid hydrolysis of DAP results from energetically favourable formation of a hydrate due to the electronic effect of the phosphonate diester. This effect also promoles ionization of the hydrate. The ionized hydrate readily expels the phosphonate diester to achieve the overall rapid hydrolysis.

scholarly journals Involvement of an arginyl residue in the nucleotide-binding site of Ca2+-ATPase from sarcoplasmic reticulum as seen by reaction with phenylglyoxal

1996 ◽  
Vol 318 (1) ◽  
pp. 179-185
Author(s):  
Senena CORBALÁN-GARCÍA ◽  
José A. TERUEL ◽  
Juan C. GÓMEZ-FERNÁNDEZ
Keyword(s):  
Atpase Activity ◽  
Calcium Binding ◽  
Reaction Medium ◽  
Order Rate Constant ◽  
Inhibition Mechanism ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Arginine Residues ◽  
Atpase Inhibition ◽  
Hydrolysis Of

1. Chemical modification of the Ca2+-ATPase with phenylglyoxal, as a modifier of arginine residues, leads to an almost total loss of the ATPase activity. The presence of nucleotides in the reaction medium protects against the binding of 18 nmol of phenylglyoxal/mg of protein and this reduction in the binding of phenylglyoxal is accompanied by a substantial retention of ATPase activity. The incorporation of phenylglyoxal to the protein alters neither calcium binding nor phosphorylation from inorganic phosphate. Nevertheless the binding of nucleotides is dramatically inhibited and, consequently, so is phosphorylation from ATP. Fluorescein 5´-isothiocyanate labelling of the phenylglyoxal-modified ATPase is not affected but, on the other hand, phenylglyoxal is not able to modify the fluorescein 5´-isothiocyanate-prelabelled ATPase. The way in which ATPase inhibition depends on the presence of phenylglyoxal indicates that this process occurs in a pseudo-first-order reaction. However, the dependence of the apparent first-order rate constant on phenylglyoxal concentration appears to be more complex and an inhibition mechanism of two steps, with phenylglyoxal binding, has to be taken into account. 2. We have found that phenylglyoxal labels both A and B tryptic fragments, but only B fragment labelling is prevented by ATP. The sequencing of peptides from mild acid hydrolysis of phenylglyoxal-labelled ATPase shows that phenylglyoxal is located in the Ala506–Gly595 peptide that is a part of the B fragment. 3. We conclude that phenylglyoxal inactivates the calcium pump in a two-step mechanism in which the second step is irreversible. Phenylglyoxal labels an arginyl residue in the Ala506–Gly595 peptide that can be protected by the binding of ATP to its site.

scholarly journals A Highly Efficient Ag Nanoparticle-Immobilized Alginate-g-Polyacrylonitrile Hybrid Photocatalyst for the Degradation of Nitrophenols

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3049
Author(s):  
Imran Hasan ◽  
Charu Shekhar ◽  
Walaa Alharbi ◽  
Maymonah Abu Khanjer ◽  
Rais Ahmad Khan ◽  
...  
Keyword(s):  
Irradiation Time ◽  
Analytical Techniques ◽  
Order Rate Constant ◽  
Order Kinetic ◽  
Ag Nps ◽  
Reaction Conditions ◽  
First Order ◽  
Order Kinetic Model ◽  
Pseudo First Order

Herein, we report PAN-g-Alg@Ag-based nanocatalysts synthesis via in situ oxidative free-radical polymerization of acrylonitrile (AN) using Alg@Ag nanoparticles (Alg@Ag NPs). Various analytical techniques, including FTIR, XRD, SEM, TEM, UV–Vis, and DSC, were employed to determine bonding interactions and chemical characteristics of the nanocatalyst. The optimized response surface methodology coupled central composite design (RSM–CCD) reaction conditions were a 35-min irradiation time in a 70-mg L−1 2,4-dinitrophenol (DNP) solution at pH of 4.68. Here, DNP degradation was 99.46% at a desirability of 1.00. The pseudo-first-order rate constant (K1) values were 0.047, 0.050, 0.054, 0.056, 0.059, and 0.064 min−1 with associated half-life (t1/2) values of 14.74, 13.86, 12.84, 12.38, 11.74, 10.82, and 10.04 min that corresponded to DNP concentrations of 10, 20, 30, 40, 50, 60, and 70 mg L−1, respectively, in the presence of PAN-g-Alg@Ag (0.03 g). The results indicate that the reaction followed the pseudo-first-order kinetic model with an R2 value of 0.99. The combined absorption properties of PAN and Alg@Ag NPs on copolymerization on the surface contributed more charge density to surface plasmon resonance (SPR) in a way to degrade more and more molecules of DNP together with preventing the recombination of electron and hole pairs within the photocatalytic process.

scholarly journals Acid Hydrolysis of Bis(2,2'; 6',2''–Terpyridyl) Iron(II) Complex in the Water Pools of CTAB/Hexane/Chloroform Reverse Micelles-A Kinetic Study in Confined Medium

2020 ◽  
Vol 15 (3) ◽  
pp. 853-860
Author(s):  
K. V. Nagalakshmi ◽  
P. Shyamala
Keyword(s):  
Ionic Strength ◽  
Acid Hydrolysis ◽  
Reverse Micelles ◽  
Order Rate Constant ◽  
Micellar Medium ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of acid hydrolysis of bis(2,2';6',2''–terpyridyl) iron(II) complex has been studied in CTAB/Hexane/Chloroform reverse micelles. The reaction obeys first order kinetics with respect to each of the reactants at all values of W, {W= [H2O]/[CTAB]}. In the reverse micellar medium, the reaction is much slower compared to aqueous medium due to low micropolarity of the water pools which does not facilitate a reaction between reactants of same charge. The effect of variation of W {W=[H2O]/[CTAB]} at constant [CTAB] and variation of [CTAB] at fixed W has been studied. The second order rate constant (k2) of the reaction increases as the value of W increases up to W = 8.88 and remains constant thereafter and it is independent of concentration of [CTAB] at constant W. The variation of rate of reaction with W has been explained by considering variation of micropolarity and ionic strength of water pools of reverse micelles with W. Copyright © 2020 BCREC Group. All rights reserved 

Compounds of 3,4,7,9,9,14,16-Octamethyl- (and 7,9,9,14,14,16-Hexamethyl-3,4-diphenyl) 1,2,5,6,10,13-Hexaazacyclohexadeca-2,4,6,16-tetraene With Nickel(II) and Copper(II). Preparations and Kinetics of Acid Hydrolysis Reaction

1988 ◽  
Vol 41 (11) ◽  
pp. 1665 ◽  
Author(s):  
NF Curtis
Keyword(s):  
Ground State ◽  
Metal Ion ◽  
Order Rate Constant ◽  
Singlet Ground State ◽  
Triplet Ground State ◽  
First Order ◽  
Order Rate ◽  
Ion Substitution ◽  
Kinetics Of ◽  
Hydrolysis Of

The complex nickel(II) cation of the bis-diazine macrocycle 3,4,7,9,9,14,14,16-octamethyl-1,2,5,6,10,13-hexaazacyclohexadeca-2,4,6,16-tetraene, omht, is formed by reaction of the complex of 3,3,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone with butane-2,3-dione, and the complex of the 7,9,9,14,14,16-hexamethyl-3,4-diphenyl homologue, bzht, is similarly prepared by reaction with 1,2- diphenylethane-1,2-dione. The cation [Cu(hmtd)]2+ is formed by metal ion substitution for a precursor of the nickel(II) cation. Compounds of the nickel(II) cations occur as singlet ground state perchlorate salts, or as triplet ground state octahedral compounds with additional ligands, e.g. [Ni(omht)(NCS)2], [{Ni(omht)(N3)}2](ClO4)2 and [Ni(omht)(en)] (ClO4)2. The singlet ground state [Ni(omht)]2+ cation in dimethyl sulfoxide converts into a triplet ground state species with first-order rate constant of 2.1(2)×10-6 s-1 at 25°C, 5.1(2)×10-5 s-1 at 50°C. The cations are slowly hydrolysed by acid, and pseudo-first-order rate constants in 2 mol l-1 HCl/NaCl for hydrolysis of [Ni(omht)]2+ and [Cu(omht)]2+ at 25° and 50°C are reported. These are of the order of 10-5 (25°C), 10-4(50°C) s-1, with a non-linear dependence on [H+], and with the reactions faster for the nickel(II) cation.

Solvolysis of exo- and endo-Tricyclo[3,3,0,02,8]oct-4-yl p-Toluenesulphonates

1975 ◽  
Vol 28 (6) ◽  
pp. 1311 ◽  
Author(s):  
RG Buckeridge ◽  
KJ Frayne ◽  
BL Johnson
Keyword(s):  
Rate Constant ◽  
Order Rate Constant ◽  
Aqueous Acetone ◽  
Subsequent Formation ◽  
First Order ◽  
Order Rate ◽  
Hydrolysis Of

The structure of endo-tricyclo[3,3,0,02,8]octan-4-ol (3; X = OH) has been confirmed by hydrogenolysis which affords the known alcohols endo- (equatorial)-bicyclo[3,2,1]octan-2-(11) and cis-bicyclo[3,3,0]octan- anti-2-ol (12). Hydrolysis of derived p-toluenesulphonate (3; X = OTs) in 70% aqueous acetone at 21.6� proceeds with a first-order rate constant of 6.67�0.21x10-4s-1, and under buffered conditions yields endo- tricyclo[3,3,0,02,8]octan-4-ol (3; X = OH) as the only observable product. The results suggest that ionization of (3; X = OTs) proceeds with participation of the C 1 to C2 bonding electrons to give the intermediate trishomocyclopropenyl cation (4) which suffers stereospecific solvent capture to yield (3; X = OH). The results obtained with the monodeuterated isotopomer (17; X = OTs) are consistent with this mechanism. Hydrolysis of exo- tricyclo[3,3,0,02,8]oct-4-yl p-toluenesulphonate (5; X = OTs) is a little slower than its epimer(3; X = OTs), and proceeds with a first-order rate constant of (1.9�0.04)x 10-4s-1 at 49.9� in 70% aqueous acetone. The mechanism in this instance appears to involve anchimerically assisted ionization and subsequent formation of the intermediate tricyclo[3,2,1,02,7]oct-6-yl cation (24)which yields a characteristic mixture of products consisting of endo-tricyclo[3,2,1,02,7]octan-6-ol(20; X = OH) (mainly), its epimer (21; X = OH), exo-bicyclo[3,2,1]oct-6-en- 2-ol (18; X =OH)and exo-bicyclo[2,2,2]oct-5-en-2-ol (19; X = OH).��� A reinvestigation of the buffered acetolysis of exo- tricyclo[3,2,1,02,7]oct-6-yl p-nitrobenzoate(21; X = OPnb) has shown that, contrary to previous conclusions, there is no leakage from the L series to the G series in this system.

scholarly journals Kinetic Study on the Hydrolysis of p-nitrophenyl picolinate Catalyzed by g-C3N4/LaNiO3-Perovskite-type Oxides

2020 ◽  
Author(s):  
Changyu Ye ◽  
Rui Wang ◽  
Haoyu Wang ◽  
Huixing Zhang ◽  
Fubin Jiang
Keyword(s):  
Sol Gel ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
X Ray ◽  
First Order ◽  
Ph Values ◽  
Calcination Method ◽  
Hydrolysis Of ◽  
Perovskite Type

Abstract LaNiO 3 -Perovskite-type oxides, as a novel hydrolytic catalyst, were synthesized using a sol-gel-calcination method, and were characterized by employing x-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET). It was revealed that LaNiO 3 and 2% g-C 3 N 4 /LaNiO 3 -Perovskite-type oxides are nanoparticles about 12 nm and 10nm easily agglomerated in large amounts, and the specific surface area of LaNiO 3 is 21.277 m 2 /g and 2% g-C 3 N 4 /LaNiO 3 is 26.645 m 2 /g, respectively. The results also indicate that there are irregular microporoes in the material. In the catalytic activity test, the absorption spectra were collected when hydrolysis of p-nitrophenyl picolinate (PNPP) (C PNPP =1-5×10 -5 mol/L) was catalyzed by LaNiO 3 (0.5g/L) and 2% g-C 3 N 4 /LaNiO 3 (0.5g/L) in buffer solution at different pH values (6.5-7.8), respectively. Based on the absorption spectrum data, the pseudo first-order rate constant is estimated to be 0.59min -1 and 1.14min -1 , respectively. In addition, the proposed kinetics model of this reaction was confirmed by the results of the spectrum and the calculations.

Spontaneous hydrolysis of heroin in buffered solution

1978 ◽  
Vol 56 (4) ◽  
pp. 665-667 ◽  
Author(s):  
Paul T. Smith ◽  
M. Hirst ◽  
C. W. Gowdey
Keyword(s):  
Liquid Chromatography ◽  
Rate Constant ◽  
Phosphate Buffer ◽  
Internal Standard ◽  
Order Rate Constant ◽  
Gas Liquid Chromatography ◽  
First Order ◽  
Order Rate ◽  
Spontaneous Hydrolysis ◽  
Hydrolysis Of

Electron-capture gas–liquid chromatography was used to study the spontaneous hydrolysis of heroin in phosphate buffer (pH 6.4 and pH 7.4) at 23 °C. Aliquots of solution were taken over a 24-h period. After extraction at pH 8.9 into propan-2-ol (10%) – ethyl acetate, deacetylated products were made into heptafluorobutyrate derivatives which were analyzed quantitatively using nalorphine as the internal standard. Heroin decomposes to O6-monoacetylmorphine (O6-MAM) under these conditions. Further decomposition to morphine was not observed. Spontaneous hydrolysis was faster at pH 7.4 (first-order rate constant, 9.6 × 10−5 min−1) than at pH 6.4 (first-order rate constant, 3.0 × 10−5 min−1). In 24 h, the decomposition to O6-MAM was 13 and 4%, respectively.

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